The present invention relates to an apparatus and a method of checking whether frame specification data stored on a recording medium coincides with an actual frame placed in a printing position in an auto-printer. In particular, the invention relates to an apparatus for and a method of detecting whether an actual frame to be printed coincides with corresponding frame specification data previously stored on a recording medium. Such frame data is used for automatic exposure correction and for printing of the frame number onto a photographic print. The actual frame number is determined with reference to splice tapes and notches of the film, and the frame specification data is stored on a recording medium during an inspection process of the film in the form of frame number, position data, and corresponding exposure correction data.
In large scale photofinishing laboratories (hereinafter referred to as photo-lab), a great number of photographic films are automatically printed in an auto-printer after the respective photographic films are inspected by a notch puncher or a negative inspection function device. The notch puncher provides a semicircular notch to each original frame to be printed, in a conventional manner and, simultaneously, records frame specification data, including frame number data, frame position data, and exposure correction data of the frames to be printed onto a recording medium, such as a punch tape or an LSI memory card. The exposure correction data is entered for each original frame to be printed during the negative inspection process. When printing, the film to be printed and the corresponding recording medium are set in the auto-printer. The auto-printer seriatim places the original frame to be printed in a print position of the auto-printer with reference to the notches, and reads exposure correction data from the recording medium with reference to the frame position data, so as to correct the print-exposure amount according to the exposure correction data.
According to the above described conventional automatic exposure correction process, if the frame position data does not coincide with the actual frame placed in the print position, it is impossible to automatically select the proper exposure correction data based on the frame position data. Such may be caused when an error occurs in a film advancing section or in a notch detecting section of the auto-printer, or by erroneous operation. Of course, if the LSI memory card itself does not coincide with the film to be printed, then the frame specification data will not coincide with the actual frame placed in the print position.
In order to detect that the actual frame position does not coincide with the frame position data, a conventional device determines, while the film is advancing, an amount of film advancement from a splice tape to a leading notch as well as individual film advancing amounts between adjacent notches. The actual film advancing amount thus determined are then compared with the frame position data recorded in the recording medium. When the actual film advancing amount does not correspond to the frame position data, it is determined that the actual frame does not correspond to the frame specification data. However, because the distances between adjacent notches are substantially constant (e.g., about 38 mm for full-size 135-type film) with little variation, it is possible to overlook or not detect the misalignment between the actual film advancing amount and the frame position data. Thus, it is difficult to obviate the misalignment without delay. Consequently, a certain number of misprints such as printing of unnecessary frames, printing under improper exposure conditions, printing of incorrect frame numbers on the back of the prints, etc. results.